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Evolution Charles Darwin. 1700’s- Natural Theology dominated the time which said adaptations of organisms was evidence that the “creator” had designed.

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Presentation on theme: "Evolution Charles Darwin. 1700’s- Natural Theology dominated the time which said adaptations of organisms was evidence that the “creator” had designed."— Presentation transcript:

1 Evolution Charles Darwin

2 1700’s- Natural Theology dominated the time which said adaptations of organisms was evidence that the “creator” had designed every species (specifically created) for a particular purpose for a particular environment.

3 *BIG DIFFERENCE BETWEEN EVOLUTION VS. CREATIONISM -Idea that all species were created at same time says they would all appear in rocks of same age but this in contrast to what paleontologists observe because some species appear than disappear in different rock layers.

4 Jean Baptiste Lamarck- (1744-1829) -published theory of evolution in 1809 (year Darwin was born) -was in charge of invertebrate collection at Natural History Museum in Paris -saw many ladders of life that species could move up (toward greater complexity) -Evolution-according to Lamark was toward greater complexity

5 Lamarck’s Mechanism for Evolution 1. Use/Disuse Parts used= larger/stronger Parts not used= deteriorate (waste away) 2. Acquired Characteristics- modifications acquired during lifetime can be passed to offspring (ex. Long giraffe neck) -NO EVIDENCE YET THAT GENES ARE CHANGED BY THIS

6 Lamarck’s theory of acquired characteristics

7 Charles Darwin-(1809-1882) born in Shrewsbury, England -read nature books- liked to fish, hunt, & collect insects as a boy -Charles earned his B.A. in 1831 & went w/ Captain Robert Fitzroy to sail on HMS Beagle -goal of the voyage  chart poorly known stretches of the South American coastline

8 Voyage of HMS Beagle

9 - Darwin spent most of his time collecting diverse/exotic species -Darwin noticed plants/animals had different characteristics than those in Europe *PUZZLING- Galapagos Islands- 900 Km west of South America but he saw animal species on Gal. that weren’t found in other parts of the world ex. Finches- 13 types collected; very similar but differed most in beaks  adapted for special diet -large ground finch- large beak for cracking seeds -small tree finch- beak used to grasp insects

10 Darwin’s finches

11 Darwin’s Findings Origin of new species Adaptation to environment *Finch results- Darwin believed that if 1 species is separated by a geological barrier they could become dissimilar to be called different species Closely related

12 Darwin’s evidence for evolution 1. Biogeography- islands  species of plants/animals that are native to island but are closely related to mainland species 2. Fossils- Bacteria  prokaryotes are earliest known fossils so they should precede all eukaryotes *Fossils do show this order (prokaryotes  eukaryotes) ex. Vertebrate record fossil fishes  amphibians  reptiles  mammals  birds

13 Darwin’s Beliefs about Evolution 1. Struggle to Survive 2. Individuals who inherit characteristics that best fit the env. will leave more offspring than less-fit individuals

14 Evolution- change in populations over time Charles Darwin- (1809-1882) -published On the Origin of Species (1859) which had 2 points: All species evolve from ancestors Mechanism for evolution  natural selection

15 Evolution according to Darwin *Natural Selection- mechanism for change in populations 1. Organisms produce more offspring than can survive ex. Fish lay millions of eggs 2. In any population, individuals have variations ex. Fish differ in size, shape, color, speed, etc.

16 Evolution according to Darwin 3. Individuals with certain useful variations such as speed are more likely to survive in their env. passing those variations on to the next generation 4. Overtime, offspring w/ certain variations (adaptations) make up most of the population, & may look entirely different from their ancestors *Modern Biologists-define evolution as a “change in a gene pool (gene frequency) of a population over time” SO, THE SMALLEST UNIT THAT CAN EVOLVE IS A POPULATION!!

17 Natural Selection This diagram shows the natural selection process for a population with dark coloration.

18 Adaptations/Structures which give evidence for evolution 1. Mimicry-structural adaptation that enables one species to resemble another species ex. Yellow jacket vs. syrphid fly (harmful) (harmless-looks like yellow jacket ) So, predators avoid eating both insects

19 2. Camouflage- adaptation that enables species to blend w/ their surroundings -survive to reproduce b/c can’t be found by predators Flounder blending in with sea floor rocks

20 3. Homologous Structures- can be similar in arrangement, in function, or both -evidence that organisms evolved from a common ancestor ex. Whale, crocodile, & bird forelimbs are similar

21 Homologous Structures

22 4. Analogous Structures- body parts of organisms that do not have a common ancestor but are similar in function ex. Wings of butterfly & wings of birds

23 . Vestigial Structures- body structure that has no function in a present day organism but was probably useful to an ancestor ex. Ostrich- has reduced forelimbs & can’t fly (ancestors probably foraged for food on land & nested on ground so they got too large to fly

24 Vestigial Structures

25 Embryology- embryo- earliest stage of growth & development ex. Embryos of fish, reptiles, birds, mammals all look the same & suggest a common ancestor

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